Yamaha Generators
I had a 25' trailer, and Honda's EU3000 generator wouldn't reliably start the AC (don't know what the rating was), although once the AC was 'warmed up' it started it and ran it fine. Now this was likely due to the 'inverter' nature of this family of generators (the problem was the internal sensors being overloaded by the sudden change in current draw to kick over a 'well rested' compressor, not the current exceeding the allowed value). I overcame this problem by installing an 'easy start' kit in my AC. This was a big capacitor and a relay, which provided an extra kick to get the AC going.
If the trailer has a 30 amp cord, I suspect the 3K generator will run the AC just fine (as long as no other high draw circuit is being used, like a microwave, hair dryer or a vaccuum cleaner). The question is whether it can START the AC. If that model is a regular, not inverter technology, generator, it probably can, and if not, an easy start kit (about $70) may give the boost it needs. Still, 3K watts is marginal for a 30 amp trailer; a 3.5K to 4K generator would be safer.
Many people use 2 Honda EU2000 connected together. Small, light, quiet, clean power, but relatively expensive and easy to steal.